PRACTICE case report Eagle’s syndrome: an unusual cause of a clicking jaw D R P Godden,1 S Adam,2 and R T M Woodwards,3

her jaw, although it could not be palpated. Calcification of the stylohyoid ligament is a well recognised There was mild ill-defined tenderness in radiographic finding in dental practice. Fortunately, affected the right retromandibular region. Exami- individuals seldom develop symptoms. We report a case of a nation of the TMJ was normal, with full patient whose main complaint was a loud click following jaw range of jaw movement, no muscle ten- derness, and no palpable click from the movement. This unusual presentation has not been described joint. Deep palpation of the right tonsillar before and should be considered in the differential diagnosis of fossa elicited tenderness. Examination of ‘clicking jaw’. the pharynx was otherwise normal. The panoral radiograph showed a thickened articulated stylohyoid process. Eagle’s syndrome was diagnosed and the patient Mineralisation of the stylohyoid ligament radiated to the ear. Her medical practi- underwent excision through an extra-oral is a well recognised radiographic finding tioner suspected internal derangement of approach. Through a skin crease incision, and an incidence of 18.2% has been the temporomandibular joint (TMJ) and the carotid artery, internal jugular vein reported on panoramic radiographs.1 advised her to consult her dental practi- and IX, X, XI and XII cranial nerves were The majority of patients are asympto- tioner. A panoral radiograph was taken dissected out and the stylohyoid ligament matic. However, in 1937, Eagle was the (fig. 1), and a diagnosis of calcified stylo- was located. The surgical findings con- first to present two cases of pharyngeal hyoid ligament was made. Upon referral firmed the presence of an enlarged and discomfort associated with elongated sty- to our unit, she was found to have a loud articulated stylohyoid process with a cap- loid process.2 Eagle’s syndrome now click upon swallowing and talking. The sule surrounding the pseudoarthrosis describes a syndrome in which there is click could be heard at mid-opening, also (fig. 2). The central section was resected elongation of the stylohyoid process with with tongue protrusion and was intermit- (fig. 3). Post-operatively the patient made associated symptoms which may include tent in nature. The patient felt that the an uneventful recovery and was free of her pain in the throat, dysphagia, dysphasia, click originated from behind the angle of symptoms. The post-operative panoral otalgia, sensation of a foreign body in the radiograph shows the residual proximal throat and facial pain which may be vague and distal parts of the stylohyoid ligament and ill defined or an acute neuralgic type (fig. 4). of pain radiating to the ear or along the In brief ● Calcification of the stylohyoid ligament is mandible.3,4 We present a case in which Discussion a common radiographic finding the main complaint was that of clicking ● It is usually asymptomatic The styloid process and ligament are upon jaw movement, an hitherto unre- ● If various symptoms such as pain in the embryological remnants of the second ported presentation. throat, dysphagia, otalgia or facial pain branchial arch and persists as a structure are present for which there is no other running from the base of the skull to the Case report obvious cause, then a diagnosis of lesser horn of the hyoid, passing between A 53-year-old female initially presented to Eagle’s Syndrome can be made the internal and external carotid arteries. her general medical practitioner with a ● Clicking is an unusual presentation. Eagle originally described two distinct 1-year history of clicking whenever she syndromes: the classic styloid and carotid moved her mandible, especially upon yawning and swallowing. The click would on occasion be associated with brief, intermittent retromandibular pain which

1Specialist Registrar, Department of Oral & Maxillofacial Surgery, North Manchester General Hospital, Delaunays Road, Manchester M8 6RL; 2Senior House Officer, Department of Oral & Maxillofacial Surgery, North Manchester General Hospital, Delaunays Road, Manchester M8 6RL; 3Consultant, Department of Oral & Maxillofacial Surgery, North Manchester General Hospital, Delaunays Road, Manchester M8 6RL REFEREED PAPER Received 24.08.98; accepted 10.11.98 Fig. 1 Panoral radiograph showing calcified stylohyoid ligament © British Dental Journal 1998; 186: 489–490

BRITISH DENTAL JOURNAL, VOLUME 186, NO. 10, MAY 22 1999 489 PRACTICE case report

artery syndromes. The classic styloid syn- drome was believed to be caused by fibrous tissue formation distorting the cranial nerve endings in the tonsillar fossa following tonsillectomy. The carotid artery syndrome was believed to be due to pressure on the sympathetic chain which Fig. 2 Enlarged and accompanies the carotid arteries, and is articulated stylohyoid not dependent upon tonsillectomy. process with capsule Although a calcified stylohyoid liga- surrounding the ment is not an unusual radiographic find- pseudoarthrosis (arrow). The hypoglossal nerve can be ing, the pseudoarticulated form is seen just below. The lower particularly unusual. It is possible that it is lobe of the ear can be seen at a consequence of fracture of an elongated the top of the picture styloid process with non-union, and pseudoarthrosis formation. In our case, it was the presence of the articulation that was responsible for the click which resolved following resection.

Conclusion Clicking jaw is a common complaint of patients in a dental practice. It is usually the result of internal derangement of the TMJ. This case report shows that a click- ing stylohyoid ligament should be consid- ered as a rare alternative diagnosis for this complaint. In this case, the click resem- bled the joint noise of internal derange- Fig. 3 The resected central section of the ment that occurs upon mouth opening. It stylohyoid ligament differed in that it was felt to originate in showing the the retromandibular region and could pseudoarthrosis also be heard on tongue protrusion which which has been opened would not occur with internal derange- ment of the TMJ. The diagnosis can easily be made with clinical examination and radiographic imaging.

1 Correll R W, Jensen J L, Taylor J B, Rhyne R R. Mineralization of the stylohyoid- stylomandibular ligament complex. Oral Surg Oral Med Oral Pathol 1979; 48: 486-494. 2 Eagle W W. Elongated styloid process: report of two cases. Arch Otolaryngol 1937; 25: 584-587. 3 Eagle W W. Elongated styloid process: further observations and a new syndrome. Arch Otolaryngol 1948; 47: 630-640. 4 Eagle W W. Symptomatic elongated styloid process. Arch Otolaryngol 1949; 49: 490-503.

Fig. 4 The post-operative panoral radiograph showing the resection margins of the right stylohyoid ligament

490 BRITISH DENTAL JOURNAL, VOLUME 186, NO. 10, MAY 22 1999